Relay



May 23, 1939- M. A. BABB E-r AL 2,159,837

RELAY Filed Dec. 25, 193B Patented May 23, 1939 UNITED STATES .PATENT OFFICE RELAY "Application December z3, 193s, serai No. 247,404

16 Claims.

The present invention relates primarily to electro-magnetic control units useful for starting and operating devices having thermionic electrodes, including among others neon and mercury vapor lamps.

As conducive to a clear understanding of the invention it is lnoted that where part of the line voltage is consumed in special mechanisms requ to heat the electrodes, with their assol@ ciated controls such as time delay relays or bimetaiiic thermal strips or other devices operated by separate heating eiements, resort to transformers or complicated resonant circuits would be required to step up the line voltage suflicienl.-

ly for enabling the arc to strike in a gas or vapor lamp.

among the objects of the invention are to provide a unit of rugged and inexpensive ccnstruction, effective to assure the expeditious zo :starting and maintenance without sputter of the operation of thermionic electrode devices of the above type, and dispensing with the need for time delay relays, thermal strips or other devices operM ated by separate heating elements or the need 251er a transformer, or for a complicated resonant circuit.

Another object is to provide a unit of the above type which automatically opens the thermionic or electrode filament circuit after the arc strikes 80 and affords ballast mechanism for limiting the current to the lamp during operation and is operative and remains operative for its purpose even though the line voltage varies several volts one way or the other as may occur in practice, espec--1 ially with small power plants.

Another object is to provide a device of the above type which is so compact that it may readily be incorporated as a unit with the lamp or disposed at will in coves or other convenient 4o places in a room to be illuminated.

UIhe invention briefly stated, involves a unit including a low reluctance closed yoke, an associated high reluctance yoke and an electro-magetic coil common to both of said yokes, a minute 4I air gap being provided in the low reluctance yoke which affords suillcient leakage to attract an armaturev on the high reluctance yoke, which in turn effects opening of a circuit maker.

- v-In the accompanying drawing in which is shown one of various possible embodiments of the several features of the invention:

Fig. 1 illustrates diagrammatically a preferred form of circuit in which the unit of the present invention is an element, the unit itself being 6I shown in plan view,

Fig. 2 is a front elevation of the unit,

Fig. 3 is a longitudinal sectional view taken on line 3-4 of Fig. 2,

Fig. 4 is a transverse secaonal view taken en the .line mi or" Fig.

W a perspe t" view of the elements up the armatm and its yoke, and

Fig. E a perspective vier-.f Witi'i pa broken away showing the main ion' reiuctance elem. nt,

For e clear-ez' unders' of the setting which the unit is prefer :iy to be refers may be had i showing such unit as of the starting and operating circuit for gaseo electric discharge devices, which circuit by itse and apart from the structure of the contrai u is the -sole invention of Maynard A. Babo and ti I subject of his copenfiing application Seriai 234,710, fried October 12, 1938 and issued April 25, 1939, as Patent No. 2,155,816.

The gaseous electric discharge device cornm prises a gas or vapor lamp i0 having a gaseous liing such as neon, mercury vapor or the like, and provided with thermionic electrodes i2 and i3 which may each be formed of a roll of electron 25 emissve material such as barium oxide, surrounding a heater filament. One terminal of electrode l2 is connected by a lead H to one tenminal i5 of a commerciai source of alternating current, which may have the usual line voltage of 110 to 120 volts. The other terminai or" eiec trode i2 is connected by lead I8 to contact plate il of a circuit maker, ccecting with contact i6 thereof, which in turn is connected by i ad i8 to one terminal of electrode I3. The other 35 terminal of electrode i3 is connected by one terminal 2li of electro-magnetic-coil ne other terminal 22 of which is connectec'i. to other terminal 23 of the power source. A hand controlled switch 2 may be disposed in either lead I 4 or i9.

The control unit in a desirable construction comprises an electro-magnetc coil 2i, rried on a spool 2G and in turn mounted upon a closed magnetic yoke or frame, a leg of which preferably extends through the coil. Desirably, said yoke is made up of a stack of E-shaped laminations 21 of iron, held together by varnish or other suitable resin. Over the median leg or bar 28 of the yoke extends the coil 2| and the lateral legs or bars 29 and 30 flank the coil. The ends of the central and lateral legs preferably extend substantially flush with the top of the coil and are connected by a bridging bar 3| of iron also made up of laminations bonded together by varnish or the like. Thus, the closed magnetic circuit extends through the coil and closely about the sides and ends thereof. The two sets of laminatlons are secured together in a unitary structure with an intervening air gap, determined preferably by an interposed layer 32 of non-magnetic insulating material, such as paper or the like. For en hancing the security of assembly of the two sets of laminations with respect to each other, the ei:- treme E-shaped larninations are preferably reversed so that the three arms 33 thereof extend downward from the cross bar or beam 3d thereof which extends along the length of the bridging bar 3i.

The closed magnetic yoke oi given dimensions is calibrated to a selectively determined low reluctance, the value of which depends on the characteristics of the lamp or otherdevice to which it is to be applied. This calibration is deteru mined by the length of the air gap or thickness of the paper layer. In practice, that thickness would be generally between .005 inch and .G30 inch, the thicker the paper the greater the reluctance. inasmuch as each line of flux passes l through two of the air gaps in series, in the particular embodiment disclosed, the eiTective length of the air gap traversed would accordingly be between .010 inch and .060 inch. Preferably paper stock of .002 inch or less would be used, and the reluctance determined by the number of sheets of paper used.

In addition to the low reluctance magnetic circuit set forth, the device presents a high reluctance circuit made up of a yoke 35 which ex-j tends through the spool 26 oi the coil, preferably against the median bar 2U and has two outstanding ends or arms 36 and 31 extending generally at right angles to the laminations, outward beyond the periphery of the spool. Yoke 35 is bridged by an amature 38 provided with' a heel piece 39 normally depressed by leaf spring ar'm it to maintain the end of the armature spaced from the lower end 31 of said yoke.

Preferably the leaf spring i6 which is riveted at one end 40 to a still insulating carrier strip 4I carries at its free end a contact 42 in normal engagement with a iixed contact 43 mounted on a metal carrier 44 also riveted to said insulating strip 4I. Strip 4I is preferably affixed upon the leg 36 of the yoke. For hingedly mounting the armature 38 on leg 36. the latter is preferably bent downward at 45 and affords an outward ledge out away at its middle to provide a pair of lateral ears 46 notched at their inner or facing edges as at 41 to accommodate the armature at corresponding lateral notches 48 which straddle the thickness of the respective ears 46, with sufficient clearance to permit ready assembly. To lock the armature against lateral shifting between the notches a non-magnetic centering plate 49 is then superposed over the armature, with its reduced end 50 snugly accommodated in the notches 41, rivets 5I forced through said positioning plate i9l and armature 38 maintaining the latter elements in assembled relation.

Preferably the other arm 31 of the yoke piece 38 mounts a shading coil in the form of one or more copper rings 52 snugly engaged about the lug 53 formed by notching said arm as at 54. Desirably the free end of the armature 38 has a pair of non-magnetic rivets 55 therein to prevent freezing of the armature to the yoke 35 in attracted position. The armature 38 and if desired also the yoke 35 is of extremely high permeability, being preferably made of an alloy of nickel and iron, such as for instance the material sold under the trade-mark Permalloy".

It will of course be understood that for assembly the yoke 35 is first inserted through spool 26, insulating carrier strip 4I with its contact maker i6, i1 is mounted upon the yoke, as is also armature 38. Thereupon the E-shaped laminations 2l are inserted through the yoke, and the bridging piece is applied and the whole subjected to a varnish bath and compressed.

The yoke 21 of the unit being made up of a multiplicity ci' iron laminations and having but a small iixed' air gap, presents high reactance and low reluctance. The magnetic leakage due to the air gap is however suicient when the current through the coil 2i exceeds a given minimum to magnetise the yoke 35 sufficiently for attrae tion of the high permeability armature 38 and thereby to cause its heel 39 to raise the spring arm i6 of the contact maker and interrupt the circuit controlled thereby. "ihe shading coil 52 causes a splitting of phase to enhance the attractive force and inhibit' chatter of the armature.

Thus, the low reluctance yoke comprises a frame, the magnetic structure of which is interrupted by minute fixed air gaps but is otherwise continuous The auxiliary or high reluctance open yoke with the armature carried thereby is arranged in parallel with the low reluctance circuit, and due to the leakage resulting from the presence'of the air gaps in the latter, will intercept enough magnetic ilux to effect attraction of the armature, when the current through the electro-magnetic coil exceeds a given minimum.

. In use ofthe unit as part of the circuit shown in Lthe line current upon closing the switch W24 passes through thermionic electrode I2, circuit rnakeriIS--l1, thermionic electrode I3 and coil 2i, which elements are at that time connected in series across the line terminals I5 and 23. The leakage of magnetic flux at the air gaps 32 of the magnetic yoke, under the current through coii`2 causes attraction of armature 38 and thereby opening of the contact maker I6-I1. This results in interruption of the circuit through coil 2| and breakdown of the magnetic field in the magnetic yoke 21 so that -the resilient leaf spring i8 recloses. This process isrepeated rapidly until electrodes i2 and I3 are suiliciently hot so that successive reactance surges from coil 2| due to the successive opening of contact I6 superadded upon the voltage across the electrodes I2 and I3A while contact i6 is open, causes an arc to be,

struck between the electrodes. tice it takes as little as one second i'or such arc to strike.

As long as the arc exists, the current thereof passes to the terminal 23 through coil 2| and is of magnitude such that the magnetic leakage is suiicient to maintain the armature 38 closed and theA contact maker I6 open. As long as the arc is maintained, the unit 2I acts as a choke, ballast, or current limiting device for the arc during continuous operation of the lamp. Preferably the unit is so designed that during normal operation the reactance thereof is approximately equal to the resistance of the lamp.

The air gap in the yoke has a two-fold function. It affords enough leakage for operation of the armature and it prevents magnetic saturation o1' the yoke, should the line voltage be increased by 5 to 10% above that for which the device is primarily designed. For, under those conditions the corresponding increase of voltage In normal prac--v across the unit effects a correspondingly great increase in reactance flux and so does not permit the lamp to take an excessive increase in current.

While, as previously noted the combined choke and contact device has its primary application i'or starting and operating gaseous electric discharge devices with thermionic electrodes, such as i'or instance neon and mercury vapor lamps, it is understood that the device is not necessarily limited to such application and it is herein claimed not only for use in such relation but as a piece of electro-magnetic equipment regardless of its particular application or use.

As many changes could be made in the above construction and many apparently widely diii'erent embodiments of this invention could be made without departing from the scope oi' the claims, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A unit of the character described, comprising an electro-magnetic coil, a stationary magnetic yoke member including a frame having a leg extending through said coil, the magnetic structure of said member being interrupted by a minute fixed air gap and being otherwise continuous, a pair of spaced magnetic arms protruding from said member and adapted to intercept magnetic ilux due to the leakage resulting from said air gap, and an armature extending between said arms and adapted to be attracted to bridge across the same when the current through said coil exceeds a given minimum.

2. The combination recited in claim l in which the eiective length of said air gap is selected between .010 and .060 inch for predetermined low reluctance of the magnetic yoke.

3. A unit of the character described. comprising a stationary magnetic yoke member including a frame, the magnetic structure oi' which is interrupted by one or more minute fixed air gaps and is otherwise continuous, an auxiliary onen magnetic yoke extending lengthwise of a portion oi said frame and having arms protruding outward from said frame. an armature extending across the extremities of said yoke arms. an electro-magnetic coil encircling said auxiliary magnetic yoke and the corresponding portion of the frame and an armature extending across the extremities of said yoke arms and adapted to be attracted and to close the magnetic circuit thereacross when the current through said coil exceeds a given minimum.

4. A unit of the character described comprising a pair of magnetic circuits, one of said circuits comprising a magnetic frame. all parts of which are relatively `immovable and interrupted by one or mc.:e minute fixed air gaps and otherwise continuous. the other of said circuits including an open yoke oi high reluctance. an armature of high permeability extending across the open ends of said yoke, and an electro-magnetic coil common to said magnetic circuits and adapted to cause attraction of said armature when the current through said coil exceeds a given minimum.

5. A unit of the character described comprising an electro-magnetic coil, a. stationary magnetic yoke structure extending through and laterally framing the ends of said coil and having paper laminations thereacross determining a minute air gap therein, a smaller yoke extendingl lengthwise through said coil and having arms extending outward from the general plane of said main yoke, and an armature pivotally mounted on one of said arms and adapted to be attracted by leakage ilux oi' suicient magnitude.

6. A unit ci' the character described, comprising an iron yoke having a leg and an electro-magnetic coil encircling the latter, said yoke including a rectangular body unitary with said leg and framing said coil, said yoke having a minute air gap aii'ording leakage iiux, an amature of high permeability and a yoke carrying the latter and arranged in close contiguity to said air gap to intercept sumcient leakage from said air )gap for attraction of said armature when the current through the coil exceeds a predetermined value.

7. A unit of the character described comprising an electro-magnetic coil, a closed low reluctance stationary magnetic circuit structure having a leg extending through said coil and aframe unitary therewith and closely embracing said coil, a high reluctance magnetic circuit including a yoke through said coil and an armature carried thereby exteriorly of said coil, said low reluctance circuit having a minute air gap, which provides sui'cient leakage flux for actuating said armature when the current through' said coil exceeds a denite minimum.

8. A unit of the character described including an electro-magnetic coil, a laminated yoke oi' low reluctance having an intermediate leg extending through said coil, a base unitary therewith under said coil, side pieces unitary with said base laterally o! said coil and a top bar bridging said side pieces and said leg, said bridging pieces and said leg and side pieces being rigidly connected together with a minute air gap therebetween, spaced magnetic elements protruding outward from the intermediate leg oi said yoke from near opposite ends of the coil, and an armature across the outer ends of said magnetic elements and adapted to close magnetic circuit therebetween when the current through said coil exceeds a given minimum.

9. A unit of the character described including an electro-magnetic coil, a laminated yoke of low reluctance having an intermediate leg extending through said coil, a base unitary therewith under said coil, side pieces unitary with said base laterally of said coil and a laminated top bar bridging said side pieces and said leg, said bridging piece and said leg-and side pieces being rigidly connected together with a minute air gap therebetween, a high reluctance circuit comprising a yoke of a single stamping extending through said coil to one side of said low reluctance yoke and having out-turned ends protruding beyond said coil and an armature of high permeability pivoted to one of said ends and operated by leakage flux from said low reluctance yoke.

l0. A unit of the character described comprising, a low reluctance magnetic yoke including a stack of E-shaped laminations an electro-magnetic coil mounted upon the intermediate leg of said yoke, the outer legs thereof flanking said coil, a stack of straight laminations bridging the ends of said three legs, paper lamination between said two sets of laminations and determining a minute air gap for leakage, and a magnetic circuit in parallel with that of said yoke and including two arms and an armature of high permeability bridging therebetween and at the exterior of said coil.

ll. The combination recited in claim l0 in which the outermost of the E-shaped laminations are in reverse positions for super-position of the beam thereof over the bridging piece.

12. A combined choke and circuit maker com-J prising a stationary magnetic yoke frame of low reluctance, the magnetic structure of which is interrupted by one or more minute ilxed air gaps and is otherwise continuous, an electro-magnetic coil encircling a portion of said frame. a second yoke through said coil extending outward at its ends substantially at right angles to said low reluctance yoke, an armature hinged upon one of said ends, a resilient circuit maker arm at right angles to the length of said armature, and across the hinged end thereof, said armature having a heel piece for directly engaging and opening said circuit maker upon the attraction of said armature.

13. 4The combination recited in claim 12 in which the part of said armature beyond the heel piece is flat and has lateral notches into which extend ngers on the high reluctance yoke to v form the hinge mount of the armature.

, 14. The combination recited in claim 12 in which the hinge of said armature is formed by a pair oi fingers on the high reluctance yoke extending transversely into lateral notches in the armature and in which the armature has a non-magnetic centering piece correspondingly notched.

15. The combination recited in claim 12 in which a non-magnetic stiff insulating strip is mounted upon that end of the high reluctance yoke which carries the armature, which strip in turn carries the circuit maker, the latter compricing a fixed contact and a resilient movable contact arm.

16. A unit of the character described, comprising a stationary, generally rectangular magnetic yoke interrupted by one or more minute xed air gaps and otherwise continuous, an auxiliary generally U-shaped magnetic yoke lying against a side of said yoke, an electro-magnetic coil closely encircling said leg and said yoke, and closely framed by said yoke, the ends of said U-shaped yoke protruding outward beyond said coil, an armature pivoted to one of said ends and adapted to engage the other oi said ends, and a shading coil encircling said other end.

MAYNARD A. BABB. SAMUEL J. A. M. BAGNO. 

